Photodefinable polyimide as an effective new material for passive photonicdevices

We report on the optical properties and the utility of photodefinable polyi mide as a new material for simple fabrication of passive photonic devices. We found that the refractive index of the polyimide could be controlled in the range of 1.5898 similar to 1.6078 for TE polarization and 1.5825 simila r to 1.5931 for TM polarization at a wavelength of 1550 nm. A waveguide pol arization splitter was fabricated utilizing the birefringent nature of this material, and its performance characteristics were found to be quite satis factory. The extinction ratios were -13.81 dB and -11.48 dB for TE and TM p olarizations. respectively, and the excess loss was less than 1.0 dB at 155 0 nm.